1. Field of the Invention
The present invention relates generally to volatile material dispensing devices, and more particularly, to a volatile material dispensing device for dispensing at a constant rate.
2. Description of the Prior Art
A number of attempts have been made to devise volatile material dispensing devices. These devices dispense perfumed fluid, aromatic oils, odor deodorizers, disinfectants, scented gels, insecticides, or the like, that scent or modify the atmosphere. Typically these devices are used in a room, vehicle, or other confined space. Volatile material dispensing devices that are designed to produce a pleasing aroma, often called air fresheners, have become common household products. Not only do these provide a sense of cleanliness and pleasantness, but they also offer the benefit of increased safety. For example, some universities do not allow the use of candles in dormitory rooms due to the fire danger, but encourage the use of safe and effective volatile material air fresheners instead.
Various systems of dispersal are known, both active and passive.
Active systems include both manual systems and powered systems. Manual systems function when a button is pushed to activate the dispersal mechanism, such as when the button is depressed on an aerosol can. By quickly spraying a quantity of small particulates, manual systems have the advantage of fast delivery, however they do not provide automatic, continuous dispersal, but require the consumer's initiation each time dispensing is desired. Powered systems, using electricity or battery power, promote the diffusion of the vapor into the atmosphere by heating the volatile material, or by increasing air circulation and turbulence around the volatile material via a fan mechanism. Active powered systems, while automatically providing continuous dispersal, do not provide a constant level of intensity. They initially provide a higher intensity that diminishes as time passes, as demonstrated in FIG. 1. Even on the Glade® website, a popular manufacturer of electrically warmed scented oils, the FAQ page informs its customers to expect that the fragrance will be stronger the first few days.
Various passive types of volatile material dispensing devices are known. Some early types called inverted bottle evaporators used a gravity-fed system. A bottle filled with the liquid was inverted in a pan to allow a pool of the liquid to form in the pan. Evaporation occurred from the pool surrounding the neck of the bottle. This type was so prone to spills that it is no longer commercially available. Some other older types, which are still offered, employ a container of an aromatic liquid or oil that is open to the air. Often a wick is provided to increase the surface area available for evaporation. These too are messy, prone to spillage, and potentially hazardous to children and pets that might access the open container. Furthermore, the consumer cannot control the dispensing rate and the intensity fades over time. Aromatic gels or semi-solids were more recently introduced. Gels are often enclosed in a vapor-permeable material and formed into a convenient, disposable cartridge. Other disposable cartridges include pads or sponge-like material permeated with vaporizable agents. The cartridges are less cumbersome and more convenient, but the dispensing rate cannot be controlled and the scent is short lived, necessitating frequent replacement. Additionally, cartridges are not able to provide a constant level of intensity over time; instead the high initial intensity drops off quickly, as shown in FIG. 1.
Accordingly, there is an established need for a convenient volatile material dispensing device that is capable of delivering a controlled, consistent flow, producing a constant intensity of vapor over time.